The plot of the film illustrates the embankment of two friends on a quest for a lost buddy, who was once an optimistic and successful student. On their journey, they recount their college life and special moments that the three shared up until their lost friend secretly parted ways after convocation. During their quest, the two encounter a rival classmate who once made a long forgotten bet with them, a funeral that goes impossibly out of control, and a wedding they must crash.

The film's soundtrack and background score were composed by Harris Jayaraj and cinematography was handled by Manoj Paramahamsa. The film was produced by Gemini Film Circuit, who had purchased the remake rights of 3 Idiots in early 2010. A lengthy and controversial delay in casting delayed filming by a year. Filming took place for a total of eight months in various locations in Europe and India.[8] The film was released on 12 January 2012 and received critical acclaim and .[9] Its dubbed version in Telugu, Snehithudu, released on 26 January 2012 in Andhra Pradesh to positive reviews.[10][11] The film was also screened at the Melbourne Film Festival.

Venkat Ramakrishnan (Srikanth), Sevarkodi Senthil (Jiiva) and Panchavan Parivendan aka "Pari" (Vijay) are three first year engineering students who share a room in the hostel of Ideal Engineering College (IEC), Chennai. Venkat studies engineering to pursue his father's wishes over his own wish – to become a wildlife photographer, while Senthil studies engineering to get his family out of poverty. Pari, on the other hand, studies engineering for his simple passion for machines and devices. He believes that one should follow excellence, not success, as success will take care of itself if excellence is followed. However, this approach to studies is sneered upon by the dean of the college, Professor Virumandi "Virus" Santhanam (Sathyaraj). Virus and the faculty favour Pari's classmate, an NRI student Srivatsan aka "Silencer" (Sathyan), who believes in mindless rote learning over understanding to reach his goals of corporate status. Pari constantly spars with Virus and Silencer due to their differences in their educational approaches.

Pari falls in love with Virus' daughter Ria (Ileana D'Cruz), a medical student, when he, Venkat and Senthil meet her when they accidentally crash her elder sister Swetha's (Anuya Bhagvath) wedding reception to obtain a free meal. Ria is not impressed with Pari's antics and complains to her father about them. Virus becomes furious with Pari and his friends and tries to break their friendship by claiming that the "rich" Pari is a bad influence on the "less privileged" Venkat and Senthil. While Venkat refuses to break his friendship with Pari, Senthil believes Virus and distances himself from Pari, though they reconcile when Pari saves the life of Senthil's paralysed father, who had suffered a heart attack, by taking him to hospital on Ria's scooter when the ambulance had not arrived on time. Ria too appreciates Pari's practicality and concern for others and reciprocates Pari's feelings. In the yearly exam, Pari stands first in his class, while both Venkat and Senthil come last. When Virus mocks Venkat and Senthil for coming last, Pari makes a bet with him; should Venkat or Senthil manage to get placed in the campus placements in their final year, Virus would shave off his moustache.

The story then moves forward by 3 years to the final year. Pari, Venkat and Senthil break into Virus's house drunk one night to allow Pari to propose to Ria. Venkat and Senthil cause a ruckus and urinate on the front door before fleeing. Virus notices Senthil and the next day, he threatens to expel him unless he snitches on Pari. Not wanting to betray his friend or let down his family, Senthil attempts suicide by jumping from Virus' office window and ends up paralysed. Following his recovery, Senthil discards his fear of the future. His frankness impresses the interviewers from a company during a campus placement drive and they hire him, forcing Virus to shave off his moustache as he lost the bet he made with Pari. Meanwhile, Venkat successfully convinces his parents to allow him to pursue his wildlife photographer dream.

Virus sets an extremely tough final exam to fail Senthil, as the job offer is contingent on graduation. When Ria learns of her father's plan, she helps Pari and Venkat to leak the question paper by providing them with the keys to her father's office. However, Virus catches them and expels them on the spot. Ria angrily confronts her father, revealing that her late brother (who was Virus' son) committed suicide because he was unable to get into IEC as his father had desired, despite having ambitions of becoming a writer. Meanwhile, Swetha, who is pregnant, goes into labour. A heavy thunderstorm cuts all power and floods the streets, making it impossible for the ambulance to reach Swetha. Pari, Venkat and Senthil deliver the baby using available equipment and an inverter developed by Pari, with Ria instructing him via VoIP. After the newborn baby is apparently stillborn, Pari manages to resuscitate the baby. Virus forgives Pari and his friends, and allows them to write their final exams. After the convocation however, Pari disappears and goes into seclusion.

7 years later, Venkat and Senthil set out on a journey to Ooty to find Pari. They are joined by Silencer, who is now a wealthy and successful professional in the USA and is looking to seal a deal with a famous scientist and prospective business associate named Kosaksi Pasapugazh. Silencer's main intention in finding Pari is to see whether Pari is more successful than him; they had made a bet in their first year of engineering on who would be more successful with their study approaches. However, when they reach Pari's house in Ooty, they find a completely different man: the real Panchavan Parivendan (S. J. Surya).

Confronting the real Pari, they find out that their friend was actually a destitute servant boy named Pappu. Pappu, who worked in Pari's household, loved learning, while Pari disliked studies. After noticing the boy's intelligence, Pari's father (Ajay Rathnam) agreed to allow Pappu to study in Pari's place instead of working as a servant. In return, Pari would pocket Pappu's qualifications and after graduating, Pappu should cut all ties with Pari and his family. Pari reveals that Pappu is now a schoolteacher in Dhanushkodi. Later, Venkat and Senthil find out that as "Pari" had disappeared, Ria had decided to marry her former boyfriend – a price obsessed banker whom she had dumped when "Pari" made her realise that he loves his expensive items more than her. Venkat and Senthil rescue Ria from her wedding in Coimbatore and they along with Silencer drive to Dhanushkodi.

At "Pari"'s school, Venkat and Senthil reunite with their long-lost friend, Ria and "Pari" rekindle their romance, and Silencer mocks "Pari" for becoming a lowly schoolteacher. He asks him to sign a "Declaration of Defeat" document for losing the bet. On seeing "Pari"'s signature, Silencer realises that "Pari" is none other than Kosaksi Pasupugazh. Silencer accepts defeat and begs Kosaksi to sign the business deal, who refuses.

"When I was shooting for Endhiran [..] I wanted to seen an action film but I ended up watching a comedy. My mind was not on the film but I saw the audience continuously laughing. I got involved in the film and I felt so good at the end of it. It was a wonderful feeling and I thought our Tamil audience must also experience this. However, Nanban is not a literal translation of 3 idiots. The movie had to be fresh and yet retain its soul. I wanted to bring it as close as possible to the Tamil audience by making it earthy and simple".

Following Gemini Film Circuit's purchase of the remake rights for 3 Idiots in January 2010, there was much speculation in regards to the three title roles played by Aamir Khan, R. Madhavan and Sharman Joshi in the original.[15] Gemini Film Circuit approached noted directors Shankar, Vishnuvardhan and S. Dharani to replace Rajkumar Hirani as the director, with the approval from Shankar leading to him being signed.[16] Despite speculation that he was set to pull out from directing his first remake as it would be a step down from his previous film, Enthiran, Shankar stated his commitment in October 2010.[17][18] He later added that, "he came across 3 Idiots during the making of Endhiran, and it was that moment he decided to break his self-imposed rule – making only original movies – and decided to direct his first remake venture."[19] As Shankar's norm music director, A. R. Rahman couldn't be retained for the project due to his busy schedules. Harris Jayaraj and Yuvan Shankar Raja were approached to compose the soundtrack,[20] with Shankar settling for the former with whom he had worked in the 2005 action film Anniyan earlier.[a] Meanwhile, Manoj Paramahamsa, whose work in Vinnaithaandi Varuvaayaa and Eeram had been critically acclaimed, was signed on as the cinematographer.[22] Sound designer Resul Pookutty and visual effects designer V. Srinivas Mohan joined the crew, following a successful collaboration in Enthiran.[23]

The Crystal Palace in Buen Retiro Park, another highlight in the song "Asku Laska"

For the lead role enacted by Aamir Khan, initial reports suggested that Suriya was the front runner, who however dismissed the link citing that his commitments had left him busy.[24] A special screening for the film industry included Vijay, who expressed his desire to work in the film, and was subsequently signed up by Gemini Film Circuits to portray the lead role.[25][26] However, by mid-December 2010, soon after trial shoots were held, Vijay walked out the film following disputes over his dates, with Suriya being labelled as his likely replacement.[27][28] Reports claimed that talks with Suriya failed, since the actor had demanded salary increase and dubbing rights for the Telugu-version of the film.[29] Suriya's reasons for refusing the offer was later confirmed not to be true, with Suriya himself revealing that he had opted out only because of other film commitments and "did not want to keep Shankar waiting".[30] As a result, Vijay was once again finalised for the role.[29][31]

The roles of the other two titular characters took considerably longer to confirm. Madhavan was initially approached to reprise his role from the original but made it clear that he was unwilling to be a part of the remake, citing the film had already "gone down in history".[32] Early indications suggested that Udhayanidhi Stalin had replaced him but the claims were false.[25] In November 2010, reports emerged that Vinay Rai or Nakul were set to play the role, however Vinay cited that he refused the project as the role was not as meaty as the other two characters.[33] Consequently, the production house signed Srikanth to play the role, after seeing his performance in Drohi, which had come after several box-office failures for him.[34] Sharman Joshi's role was originally offered to Silambarasan, but after discussions, it was revealed that Silambarasan could not associate himself with the character.[35] Subsequently the role was offered to Siddharth, a protege of Shankar, who also went on to refuse the project.[36] Despite further reports that Arya and Jiiva were being considered, the latter signed on and agreed with Shankar that he would play Joshi's role instead of Madhavan's.[37][38] The role played by Kareena Kapoor in the original was reported to be played by either Shruti Haasan or Asin. However Ileana D'Cruz was signed on for the film after attempts to cast Katrina Kaif in the film had failed.[39] The college professor's role was given to Sathyaraj, despite early indications that Prakash Raj would be approached. Omi Vaidya was unable to reprise his role from the original and comedian Sathyan Sivakumar was signed on to essay his role after attempts to sign Sricharan of Payanam fame has failed, while S. J. Surya signed on to appear in a guest role, portraying the role enacted by Javed Jaffrey.[40][41]Anuya Bhagvath was signed up for a supporting role.[42] Stage artist Sreedevi Gengiah was selected to play Jeeva's sister.[43]

Shankar wanted to paint a train for the song sequence, so the team decided to stick paper and then paste the painting on it. Art director Muthuraj hired some 250 artists from various states who were well versed in folk drawings and finished the entire job at breakneck speed and returned the train in time.[57]

The album received positive reviews. IndiaGlitz.com wrote that the music album is "ready to mesmerize you".[64]Behindwoods.com labelled it a "winner all the way", adding that it had "good variety all through the album [...] and ample scope for festivities in the theater".[62]Top10cinema.com wrote that it had three songs that "strike spectacularly with its rich music and commendable lyrics", calling it a "good work by Harris".[65]600024.com mentioned: "Overall, this Nanban is your well-Known Friend".[61]KollyTalk.com called it "Youthful and refreshing".[66] On the contrary, Pavithra Srinivasan from Rediff wrote that there was "nothing new about the music in Nanban", concluding that Harris Jayaraj had "obviously taken the safe route, sticking to his usual template for most of the songs in this album".[63]

The film is a remake of Rajkumar Hirani's 3 Idiots (2009),[5] which itself was adapted from the novel Five Point Someone – What not to do at IIT! by Chetan Bhagat.[6] The film deals with the theme that one shouldn't run behind success and rather pursue his/her own interests. If one develops right skill anything is possible.[67] According to Gauthaman Bhaskaran of Hindustan Times, "Nanban’s message is profound [..] given India’s exploitative and unimaginative education system. The film lambasts bookishness, the mad chase for marks, [..] the joy of discovering. Parental and peer pressure and the frightfully huge fees for professional courses push boys and girls into performing puppets. The higher your grades, the closer you are to securing a centum, the brighter become your chances of making it in life".[68]

The film shows characters having various interests. The character Pari is against the educational system and insists his classmates not to run behind grades rather derive pleasure by understanding and assimilating things while his principal Virumandi Sandhanam aka Virus (Sathyaraj) wants students to become a book worm to excel in academics. Venkat is interested in wildlife photography but his parents compel him to study engineering. Senthil hails from a poor family and is compelled to study professional course only to bail out his family from all troubles.[67]

The film also uses real inventions by little-known people in India's backyards. The brains behind the innovations were Remya Jose, a student from Kerala, who created the exercise-bicycle/washing-machine; Mohammad Idris, a barber from Meerut district in Uttar Pradesh, who invented a bicycle-powered horse clipper; and Jahangir Painter, a painter from Maharashtra, who made the scooter-powered flour mill which was featured in the original Hindi film.[69]

Prior to the release, Nanban was voted the "most expected film" of 2012 through an online public poll conducted by Vikatan.[70] The film was released on 12 January 2012 for Pongal in 925 screens worldwide.

Nanban advance booking opened well in Chennai city and suburbs.[71] It had the highest number of 77 shows in a single day at Mayajaal multiplex in Chennai at that time.[72][73] The film opened in nearly 625 screens in Tamil Nadu.[8] It was released in 50 screens in Chennai[74] and 31 screens in Hyderabad.[75] It released simultaneously in UK, the US, Malaysia and Singapore.[76]Nanban became the first Tamil film to be released with French subtitles in France.[77] It also became the first film to get exempted from the 30 percent entertainment tax in Tamil Nadu by the new scheme introduced by the Government of Tamil Nadu.[78]

The Television broadcasting was sold for a record sum to STAR Vijay for ₹120 million (US$1.9 million).[80][81][82] Indian DVD were marketed by Moser Baer.[83] Overseas DVD were marketed by Suara DVD.[1]

Sify called it an "engaging film with noble intentions. It deserves viewing because films like this are hard to find".[84] Behindwoods.com rated the film 3.5/5 and wrote: "Nanban has got more than something for everyone. It is very unlikely that a person finds such a wholesome package unsatisfying. All is absolutely well!"[85] Pavithra Srinivasan from Rediff.com gave the film 3/5 stars, describing it as "the perfect feel-good fare for the festive season, despite minor glitches".[86] Malathi Rangarajan from The Hindu wrote: "Nanban is an enjoyable cocktail of humour with some sentiment and sadness thrown in for that extra appeal. Once again Shankar proves the master craftsman that he is".[87] Anupama Subramanian from Deccan Chronicle gave the film 3/5 stars, while labelling it as a "feel-good film with a larger message and a brilliant feat by Vijay which makes the film a not-to-be-missed one!"[88] Venkateswaran Narayanan from Times of India wrote: "All is well with Nanban because Shankar's retelling of 3 Idiots retains its soul and has its heart in the right place".[89]Zee News wrote: "Nanban is a must watch, grab your tickets now. It’s the best gift Vijay could have given to his diehard fans this Pongal".[90] IndiaGlitz.com named it a "clear entertainer", "a whiff of fresh air from the mindless masala movies" and a welcome change".[67] Rohit Ramachandran of nowrunning.com rated it 3/5 stating that "Nanban is Rajkumar Hirani's 3 Idiots staged and presented by Shankar in a different language with grandeur. The base material is solid and Shankar obediently traces it. Out comes an uplifting entertainer that will draw raves from viewers of all kinds".[91]Oneindia.in gave a positive verdict and wrote, "All is well. It is a Shankar's Sankrathi feast for the audience! Do not hesitate to watch Nanban even if you have seen 3 Idiots".[92]CNN-IBN said that it was "sweet and satisfying".[93] Acclaimed actor Kamal Hassan appreciated Vijay's performance in the movie and lauded the team's effort in making such a good entertainer.[94][95][96] At the Internet Movie Database the film stands up with a rating of 7.8 out of 10 stars.[97] Jeevi from Idlebrain.com with regards to the Telugu dubbed version Snehithudu commented that "the magic of 3 idiots is missing", and gave 3/5 stars.[98] Indiaglitz stated that Snehithudu was a "passable remake".[99] On Rotten Tomatoes, the film holds an audience rating of 96% based on nearly 1200 votes.[100]

In Chennai city, the film netted ₹22.7 million (US$350,000) in its first weekend and 64% of the takings,[101][102] and ₹49.5 million (US$770,000) at the end of the first week, staying at first rank.[103][104] The film accounted for 66% of the takings at the Chennai box office on its second weekend[105] and 64% on its third weekend.[106] The film grossed around ₹78.9 million (US$1.2 million) in Chennai after seven weeks,[107] out of which about ₹10 million (US$160,000) came from Sathyam Cinemas multiplex.[108] In Coimbatore and Nilgiris area, Nanban opened in 70 screens and netted ₹52 million (US$810,000) in the first week.[8] It also got a great opening at the Bangalore box-office,[109] where it was still featured in Top 5 even one month after its release.[110] The film's gross collection after its first week from 4 circuits of Coimbatore was around ₹55 million (US$860,000), the highest yield since Endhiran.[111] The movie entered the ₹100 crore (US$16 million) elite in just 15 days[112] The film completed a 100-day run at the box-office on 20 April 2012.[113]

Nanban was released in 7 screens in Australia and grossed $76,580 in its first weekend.[114] Overall it had grossed $110,422.[115][116] In UK, it collected $173,789 in its first week with a per screen average of $7,241 in 24 theatres. After its 4-week run the film collected £214,735 (₹16.6 million) and became the 4th highest grosser in UK.[117] It also secured the first place in the Malaysian box-office in the first week released in 37 screens,[118] and collected a total of $871,959 after a six-week run.[119] It collected a sum of ₹5.8 million (US$90,000) after 18 days at the Australian box office, whereas it had collected ₹38.2 million (US$600,000) at the Malaysian box office within the same period.[120]